The present invention relates generally to an inflatable cushioning device for body supports such as a mattress, sofa, or chair cushion. In particular, the present invention relates to a body support for preventing the formation of pressure induced soft tissue damage.
Heretofore, inflatable cushioning devices for use with body supports, such as a mattress, sofa, seat, or the like, typically included a plurality of air cells or bladders that are inflated to support a person. The air cells provide support to the person, and can be inflated to a desired pressure level to provide the person with a predetermined level of comfort and support.
In the medical field, cushioning devices including a plurality of air cells are often used to provide different levels of support under various portions of a patient""s body. For example, a mattress may include separate air cells located in the upper, middle, and lower portions of the mattress. These air cells can be inflated to different pressures to support the upper, middle, and lower portions of the patient""s body with different pressures.
In hospitals which provide care to patients confined to a bed for extended periods of time, the patients often suffer from the effects of excess pressure transmitted to their bodies. As known in the medical field, continuous pressure applied to a patient""s body can cause soft tissue damage. When the external pressure exerted on the patient""s skin causes blood carrying capillaries to close, soft tissue degeneration may occur. This soft tissue damage may lead to the formation of pressure sores. For example, continuous pressure applied to a patient""s heel can cause a pressure sore to develop on the heel. The multi-cell cushioning devices described above can be used to relieve the pressure applied to a specific portion of a patient""s body. In the case of a patient""s heel, for example, this may be accomplished by inflating the air cell under the patient""s leg so that the heel is lifted from the mattress. Thus, the continuous heel pressure is relieved and the formation of a bed sore on the heel is prevented.
Air cushion devices typically require an external pump to inflate the air cells in the device. Alternatively, the air cushion devices are pre-inflated in the manufacturing plant and are shipped to a field location for use. A problem may develop when the atmospheric pressure at the inflation location is different from the atomospheric pressure at the field location where the device is used. For example, if the field location atmospheric pressure is lower than the atmospheric pressure at the inflation location, the air cells in the field will expand and become firmer.
Hospitals rate pressure relief support systems as xe2x80x9ctreatment productsxe2x80x9d if they sufficiently reduce the pressure upon a patient""s body, reduce tissue trauma, and facilitate the healing of skin ailments, such as burns, pressure sores, etc. Typical pressure relief support systems which qualify as xe2x80x9ctreatment productsxe2x80x9d are embodied in beds which contain motors and pumps to vary the shape and pressure within the mattress. Such beds are very expensive and require the operator to undergo extensive training to learn how to use and operate the system. Furthermore, the xe2x80x9ctreatment productsxe2x80x9d often require extensive maintenance due to the failure of the numerous moving mechanical parts. Also, these complicated pressure relief support systems cannot be used on typical box spring mattress supports, and require specialized bed frames. The complicated design of these beds makes their repair very difficult, and often requires the complete replacement of the entire system for proper servicing. A further difficulty is that during power outages, these mattresses lose pressure leaving a patient on a hard surface to develop pressure sores if action is not taken. Thus, a need exists to arrive at a body support which adequately addresses these disadvantages.
The present invention provides a cushioning device for a mattress, seat, sofa, or the like where support is obtained from a fluid such as atmospheric air. The cushioning device has few moving parts, is user controllable, requires minimal maintenance, and is easily repairable. The cushioning device of the present invention includes a support system apparatus, a sleeve apparatus, a jacket, a topper cushion, and an outer cover.
The support system apparatus includes at least one support cell for providing lifting support for a body. Each support cell includes an envelope containing a fluid. Application of an external load on an outer surface of the envelope causes the envelope to deform into a compressed form. The envelope includes a reforming element that is capable of providing a reforming force to the interior surface of the envelope, to return the envelope to its original unloaded form. The reforming element is preferably made from a resilient foam material, however, other resilient means can be used.
An intake valve and an exhaust valve are included in each support cell. The exhaust valve in each support cell is connected to an exhaust control system. The intake valve in each support cell is connected to an intake control system. Each intake valve includes an intake check valve allowing fluid to flow into the support cell, while preventing fluid from flowing out of the support cell. Each exhaust valve includes an exhaust check valve allowing fluid to flow out of the support cell, while preventing fluid from flowing into the support cell. The intake control system is connected to a fluid supply reservoir. The exhaust control system is connected to a fluid exhaust reservoir. Preferably, the fluid included in the supply and exhaust reservoirs is air, however, any suitable fluid, e.g., water or nitrogen, can be used. The fluid supply and exhaust reservoirs may comprise the same reservoir, and may comprise an ambient source of fluid such as atmospheric air.
In use, the weight of a body of a person, patient, or animal resting on the envelope deforms the envelope. For illustration purposes, a patient will be used as an example of a body resting on a the envelope. The pressure of the fluid within the envelope increases as the volume of the envelope decreases under deformation. As the pressure of the fluid increases, the fluid in the envelope flows out of the envelope through the exhaust valve and into the exhaust control system. Next, the fluid flows from the exhaust control system into the fluid exhaust reservoir. Furthermore, as the envelope deforms to conform to the irregular shape of the patient, the area of the envelope supporting the load increases. Equilibrium is achieved when the forces within the envelope, including the pressure of the fluid within the envelope multiplied by the area of the envelope supporting the load, plus the force provided by the reforming element equal the weight of the load.
A controllable pressure relief valve is included in the exhaust control system so that a maximum pressure level of the fluid within the envelope can be set and maintained. Different selected maximum pressure levels of the fluid allow the support cell to accommodate different weights or allow different degrees of conformation between the patient and the envelope surface. Preferably, the maximum pressure level of the fluid is set to ensure that the interface pressure under the entire contact surface of the patient is below the pressure that may cause soft tissue damage such as pressure sores to occur.
As the weight of the patient is removed from the support cell, the reforming element exerts an outward force on the interior surface of the envelope. As the envelope expands, a partial vacuum is created in the interior space of the envelope, causing fluid to be drawn back into the interior space of the envelope. The fluid is drawn from the fluid supply reservoir into the intake control system, through the intake valve, and into the interior space of the envelope. The intake valve includes a one way intake check valve that permits fluid to re-enter the interior space of the envelope, while preventing fluid from exiting the interior space of the envelope.
The support cells included in the present invention can use atmospheric pressure as the pressure source for inflation. Therefore, when the fluid supply and exhaust reservoirs comprise atmospheric air, inflation can be accomplished without the need for expensive blowers, pumps or microprocessors as required by previously available xe2x80x9ctreatment products.xe2x80x9d A plurality of support cells can be interconnected with the intake control system and the exhaust control system to create a support system apparatus. The support system apparatus can support a patient by providing self adjusting pressure management to the entire contact surface of the patient. The support system apparatus provides a low interface pressure under the entire surface of the patient being supported. For example, if the patient is lying on the support system apparatus, the support system apparatus ensures that the interface pressure under the entire contact surface of the patient is below the pressure that may cause soft tissue damage to occur.
The support system apparatus also has the ability to self-adjust every time a patient moves, or is repositioned on the support system apparatus. When the pressure distribution applied to the support system apparatus changes, the support cells within the support system apparatus automatically inflate or deflate as necessary, to maintain a low interface pressure under the entire patient.
Another embodiment of the current invention provides for separately controlled support zones within the support system apparatus. Each support zone comprises at least one support cell. Each support cell includes at least one intake valve and at least one exhaust valve. The intake valve for each support cell in each support zone is connected to the intake control system. The exhaust valves from each support cell in a single support zone are connected to a single exhaust control system. Each support zone has a separate exhaust control system. The intake control system is connected to the fluid supply reservoir. The exhaust control system for each support zone is connected to the fluid exhaust reservoir. Generally the pressure level in each support zone is set at a different level. For example, if the support system apparatus comprises a mattress in a bed, the upper, middle, and lower zones of the support system apparatus can be set to provide a different level of pressure or firmness for the upper, middle, and lower portions of the patient""s body.
The sleeve apparatus includes a cell cover surrounding each support cell. For a plurality of support cells, each cell cover is attached to an adjacent cell cover. The cell cover allows the surface of the envelope of the support cell to slide freely along a first side of the cell cover, without transmitting this sliding movement to a second side of the cell cover. The second side of the cell cover can be the side on which a patient is lying. Therefore, movement of the support cell is not transmitted to the patient, thereby preventing frictional or shear force abrasion damage to the skin of the patient. In the event that repair of a support cell becomes necessary, the sleeve apparatus allows each support cell to be easily removed and replaced.
Another embodiment of the present invention provides an additional alternating pressure system for providing alternating supply pressure to a plurality of zones. The alternating pressure system can be used in combination with the support system apparatus. Each zone includes at least one support cell. The alternating pressure system includes a pressurized fluid supply source including a pump, a pressurized fluid tank, etc. Additionally, the alternating pressure system includes a control system for sequentially supplying fluid pressure to the plurality of zones. The raising and lowering of the alternating zones under a patient provides beneficial movement of the skeleton and tissue in the patient. The movement helps stimulate circulation and lymph fluid movement in the patient. When the alternating pressure system is deactivated or fails, the support system apparatus continues to provide self adjusting pressure management to the patient""s body.
The jacket houses the support system apparatus, the intake and exhaust control systems, and portions of the alternating pressure system. The jacket can be made from any suitable stretchable material, and is preferably is formed from a stretchable fabric material.
The topper cover provides further resilient torso support. The topper cover may be formed from a layered fiber filled material or other suitable material. The topper may include a resilient heel support unit to reduce pressures on the sensitive heel region of a patient. The topper cover may rest above the jacket, and may be covered by the outer cover. Alternatively, the topper cover may rest above the support system apparatus.
The outer cover provides a low friction and low shear surface further protecting the patient from frictional tissue damage. Additionally, the outer cover provides a waterproof and stain resistant surface. For medical uses the outer cover can be made from an anti-microbial type material.
The cushioning device of the present invention allows a user in the field to adjustably set the maximum pressure level in each support cell. When surrounded by atmospheric air, the support system apparatus is self-inflating, self-adjusting, and does not require expensive pumps and control systems as required by related xe2x80x9ctreatment productxe2x80x9d art. Also, since there are fewer moving parts in the present invention, maintenance and repairs are simple and reasonable in cost compared to the complex related art.
The cushioning device of the present invention can be used in combination with any support device where self adjusting dynamic pressure support of the person or patient is required. For example, these support devices can be mattresses, sofas, seats, etc.
Generally, the cushioning device of the present invention comprises:
a plurality of fluid cells; and
a non-powered manifold system, operatively attached to the plurality of fluid cells.
The present invention additionally provides a cushioning device comprising:
a plurality of self-inflating fluid cells;
a manifold system, operatively attached to the plurality of self-inflating fluid cells; and
means, operatively attached to the self-inflating fluid cells for adjusting the firmness or softness of all of the fluid cells.
The present invention additionally provides a cushioning device comprising:
a plurality of self-inflating fluid cells;
a manifold system, operatively attached to the plurality of self-inflating fluid cells; and
a pressure regulator attached to the manifold system.
The present invention additionally provides a cushioning device comprising:
a plurality of fluid cells;
a pressure regulator; and
a manifold system, operatively attached to each of the fluid cells, wherein the fluid cells do not communicate with each other through the manifold and all fluid cells communicate with the pressure regulator.
The present invention provides a method for supporting a body comprising:
providing a plurality of non-powered self-inflating fluid cells;
applying a body weight to the non-powered self-inflating fluid cells; and
allowing each of the non-powered self-inflating fluid cells to react to the body weight and adjust to an identical internal pressure.